Fuel pump



May 19, 1936. H, GRUBBS FUEL PUMP Filed Nov. 15, 19:54

IIIIIIII l l V www@ Patented May 19, 1936 ,UNITED STATES .PATENT OFFICEFUEL PUMP Hayward I. Grubbs, El Monte, Calif. Application November 15,1934, Serial No. '153,202

5 Claims.

- This invention relates to fuel pumps, intended primarily for but, ofcourse, not limited to use upon Diesel engines and has for its objectthe provision of means whereby the stroke of the pump may be varied tosuit conditions. It is also an object of the invention to provide anapparatus which will be silent in operation and which will operateeasily and smoothly at all times. It is also an object of the inventionto provide simple means for regulating the stroke of the pump. Oneembodiment of the invention is illustrated in the accompanying drawingand will be hereinafter fully described, the novel features beingparticularly dened in the appended claims.

In the drawing:

Figure 1 is a vertical section through a fuel pump embodying theinvention.

Figure 2 is a horizontal section on the line 2-'2 of Figure 1.

Figure 3 is a vertical section on the. line 3-3 of Figure 1.

In carrying out the present invention, there is provided a casing orfuel chamber I, the sides of which are elongated to provide a crankchamber 2 in which the driving shaft 3 operates, said shaft having a cam4 thereon which has a straight face and a curved face and which isslightly attened at a point diametrically opposite its high part, asclearly shown, so that the upstroke of the plunger will be sharp, whilethe downstroke of the plunger will be more or less retarded, therebyavoiding shocks to the mechanism and noise in the operation. Within thecasing I is a cylinder 5 delning, with the casing, a chamber 6containing oil or some other non-compressible fluid. The oil chamber maybe provided with a lilling opening at any convenient point, and in thecyllnder, intermediate the ends thereof, are ports 1 'establishingcommunication between the oill chamber and they interior of thecylinder. A plunger 8 is mounted in the cylinder and rests upon the cam4 to be operated thereby, and in said plunger 8 is an axial chamber 9receiving an expansion coiled spring Ill, as shown. Above the port 1,the cylinder is provided with an annular flange II constituting a stopfor an upper plunger I2, 'the spring I0 bearing 'at its upper endagainst the lower endof said upper plunger. Secured toand rising fromthe upper plunger is -a piston I3 which has its upper end working in apump cylinder I4 which rises from and is supported by a frame I5 securedto a post or an'ge I6 on the casing I. The pump piston I3 fits snuglybut slidably within the cylinder I4 and below the frame I5 carries anabutment or washer II between which and said frame I5 is disposed abuier spring I8. 'I'he pump cylinder I4 has an inlet pipe I9 fittedthereto and in said pipe, immediately adjacent its juncture with the 5cylinder, is a check valve 20 which will permit flow into the cylinderbut prevent ow therefrom. The outlet for the fuel is furnished by theupper end of the cylinder I4 which leads to the cylinder of the engineand in said outlet, immedil0 Y ately above the inlet pipe I9, is a checkvalve 2| which will permit flow to the outlet but prevent ow therefrom.

Slidably but closely fitted upon the cylinder 5 is a collar 22 which isadapted to cover the ports 15 'I except the lowermost port which lisalways open. The ports are so arranged that the port on one side has itstop wall alined with the bottom wall of the port on the opposite side,this arrangement obtaining the eiect of a continuous opening or 2o slot.The collar 22 is provided with a tubular offset 23 in which is mounted acheck valve 24 which will permit ow into the tubular oiset and the spacebetween the plungers but willl prevent flow therefrom. Pivoted to thecollar 22 at dia- 25 metrically opposite points thereof are links 25which extend upwardly through the top of the oil chamber andare pivotedat their upper ends to a yoke or fork 26 fulcrumed upon a lug 21 on thetop ofthe oil chamber. The forkv or yoke 26 30 spans the pump piston I3,as clearly shown, and from its bridge an arm 28 projects over the oilchamber. Journaled in lugs or ears 29 on the top of the oil chamber is agovernor rod or shaft 30 which may be connected in any approved manner35 with .the governor of the engine or may be equipped with meanswhereby it may be set by hand. Immediately under the arm 28, a crank 3|is formed on or secured to the shaft and bears against the underside ofthe arm in opposition 40 to a contractile spring 32 which is attached tothe free end of the arm and to the wall of the casing I, as shown inFigure 1. To obtain uniformity in the adjustment of the collars upon allthe cylinders of a multiple cylinder engine, a set screw 33 is mountedin the arm 28 and bears against the end of the crank 3|, as will beunderstood. Slight turning of this set screw may be j It is thought theoperation will be readily understood from what has been said. On theupstroke of the lower plunger oil in the space between the two plungerswill be trapped and the movement of the lower plunger will, therefore,`

be transmitted to the upper plunger so that the pump piston I3 will beraised and any fuel that may be in the cylinder I4 above said pistonwill be driven past the check valve v'll to the engine cylinder. Uponthe downstroke, the weight of the upper plunger I2, together with theexpansion of the spring Il, will cause the same to descend and theexpansion of the spring I0 will cause the lower plunger to follow themovement of the cam 4 so that it will also be lowered. Upon thedownstroke of the piston I3, another charge of fuel will be drawnthrough the fuel inlet pipe I 9 past the check valve 20 to be driven tothe engine cylinder upon the ensuing upstroke of the pump piston. Ii'the controlling collar 22 be set as shown in the drawing so that onlythe lowermost port 'I is open, the trapping of the oil between the twoplungers will occur at the beginning of the upstroke of said plunger sothat the upper plunger I2 will be moved at once and its stroke will beapproximately the same as the stroke of the lower plunger and a fullcharge of fuel will be driven to the engine cylinder. Should the enginebe idling or running at a very slow speed, the collar 22 will be raisedso 'that one or more additional ports 'I will be uncovered and,consequently, as the lower plunger moves upwardly some of the oil aboveit will be driven out through theAopen ports and trapping will occur ata later point in the stroke so that the stroke of the upper plunger willbe relatively shortened and less fuel will be driven into the enginecylinders and at a longer interval. 'I'he feeding ot the fuel may bethus advanced or retarded. The check valve 24, mounted upon the cutoifor regulating collar, serves to break any vacuum that may possibly beformed between the' plungers on the downstroke so that the space betweenthe' plungers will always be illed with oil, although, as Justexplained, the trapping of the oil will occur sooner or later in thestroke of the lower plunger according to the adjustment of the collarand, consequently, the stroke of the fuel pump will be varied. Themechanism is compact,

simple and easily manipulated so that it is not apt to get out of orderand will operate eiilciently to regulate the stroke of the pump.

Having thus described the invention, what is 'claimed as new is:

1. A device of the class described comprising a chamber to hold anon-compressible fluid, a cylinder in the chamber provided with a.series of ports between its ends to establish communication with thechamber, a lower plunger in the cylinder, means for raising and loweringsaid plunger, an upper plunger in the cylinder, means for limiting thedownstroke of the upper plunger whereby it will be supported above theports in the cylinder, a cut-off slidably mounted on the cylinder tocover and uncover the ports, a check valve mounted on said cut-off andpermitting ow into' the same, and means for adjusting said cut-off, saidports permitting entry of uid between the plungers to establish anhydraulic connection therebetween.

2. A device of the class described comprising a uid containing chamberhaving an inner cylindrical wall, a series of ports in the innercylindrical wall of said chamber, said ports being arranged to, ineffect, form a continuous opening, upper and lower plungers mountedwithin the inner cylindrical wall of the uid chamber, an expansionspring between the plungers, means for raising the lower plunger to ridepast the ports in the cylindrical wall, a cut-ofi slidably mounted onsaid wall in the fluid chamber and adapted to cover or uncover saidports, a check valve mounted on said cut-off to admit flow thereinto,and means for vertically adjusting said cut-off, said ports permittingentry of a non-compressible iiuid between the plungers for cooperatingwith the spring and connecting the plungers.

3. A device oi' the class described comprising a fluid chamber having aninner cylindrical wall and ports in said wall between the upper andlower ends of the same, upper and lower plungers mounted in thecylindrical wall of the chamber, respectively above and below saidports, an operating cam engaging the lower end of the lower plunger, anexpansion spring between the plungers, a cut-oil slidably mounted on thecylindrical wall of the fluid chamber and adapted to cover or uncoverthe ports therein, a pivoted arm on the top of the fluid chamber, linksconnecting said arm with the cut-olf, and means for setting said armwhereby to adjust the regulating cut-off, said ports permitting entry ofa non-compressible iiuid between the plungers for providing an hydraulicconnection between said plungers.

4. A device of the class described comprising a fluid chamber, acylinder extending through said chamber and having ports between itsends, upper and lower plungers working in said cylinder above and belowthe ports, respectively, means for operating the lower plunger, aregulating cut-olf mounted on the cylinder to ccver or uncover theports, an arm pivoted on the top of the fluid chamber and extendingbeyond the same, links connecting said arm with the cut-ofi', a governorshaft journaled on the top of the uid chamber, a crank on said shaftbearing against the underside of the pivoted arm adjacent the free endof the same, and yieldable means connected with the free end of the armto maintain it in engagement with the crank, said ports permitting entryof carrying amounts of a non-compressible fluid between the plungers forproviding a variable hydraulic connection therebetween.

5. A device of the class described including a fluid chamber having acylindrical wall and ports in said wall, plungers mounted in the chamberrespectively above and below said ports, operating means for one of theplungers, tensioning means lbetween the plungers, slidable means mountedon the chamber and adapted for covering or uncovering the ports, meansfor operating said slidable means, and a set screw for adjusting thelast mentioned means, said ports permitting entry of uid between theplungers for providing an hydraulic connection therebetween.

HAYWARD I. GRUBBS. Y

